Liberia has struggled to track down 17 suspected Ebola carriers who fled quarantine at the weekend, while the UN health agency urged affected west African nations to screen all departures in a bid to contain the worst outbreak of the virus.

Armed men claiming "there's no Ebola" in Liberia have raided a quarantine centre for the deadly disease in the capital Monrovia, prompting at least 20 patients infected with the deadly virus to flee, a witness said.

As the World Health Organisation (WHO) rules people infected in the West African Ebola outbreak can be offered untested drugs, the scarcity of supplies has raised questions about who gets priority access to treatment.

A World Health Organisation (WHO) panel of medical ethics experts have ruled that it is ethical to offer unproven drugs or vaccines as potential treatments or preventions in West Africa's deadly Ebola outbreak.